1. Field of the Invention
This invention relates a cover apparatus for a manhole, pipe or valve, and more particularly to a secure cover for manhole, pipe or valve cover utilizing an expandable bladder that fits around the outer circumference of the depending side wall of the cover. The expandable bladder, provides a secure seal between the cover and the access opening. An externally flared side wall extends below the depending side wall, to improve the seal between the expandable bladder and the access opening.
2. Description of the Prior Art
Water, sewer and electrical wiring is typically buried under public right of way, such as streets, alleys and easements. Access openings are spaced at intervals throughout the system of pipes. The access openings with normally open valves are incorporated for the purpose of selectively isolating sections of the pipe in the event of a break or leak in the system. Shut off valves are frequently buried several feet below the street. Access pipes extend upward from the buried valve to the surface to provide a passage for a tool to selectively actuate the valve between on and off positions. A mechanical cover assembly having a removable cover has traditionally been used to prevent debris from entering the access pipe. The cover assembly typically includes a cast iron cover with a mechanical locking apparatus to secure the cover to a concrete casting which supports the cover.
Drain and water lines are usually installed before the road or site grading begin. Manhole access holes to sewer systems are also placed in public rights of way, and are spaced at intervals throughout the system. Drainage gates are used to drain parking areas and other large surface areas. Drainage gates use slotted covers, and are also connected to the sewer system.
What is needed is a temporary cover that will easily conform to the rough and often unfinished surface of the concrete manhole vault. The temporary cover will stop dirt from being pushed into the sewer line during grading or road construction. Currently, large steel plates are placed over these manhole vaults, and are later removed when the final cast and ring setting work is complete. Steel plates provide a poor fit, and do not stop vandals from intruding into the sewer line during construction. Valve access covers are disclosed in the following prior art:
U.S. Pat. No. 6,109,822 issuing to Campbell et al. on Aug. 29, 2000 discloses a valve access cover assembly having an annular resilient flap.
U.S. Pat. No. 6,073,792 issuing to Campbell et al. on Jun. 13, 2000 discloses an access cap having a movable retaining tongue engageable with a portion of an access structure to retain the cap on the structure.
U.S. Pat. No. 5,439,130 issuing to Waugh on Aug. 8, 1995 discloses a debris cap with a locking post that is insertable into an opening in the closure of the cap.
U.S. Pat. 4,921,123 issuing to Mizioch on May 1, 1990 discloses a debris cap for closing the end of an access pipe for an underground water shut-off valve.
Pipe plugs are disclosed in the following prior art:
U.S. Pat. No. 6,289,935 issuing to Tash on Sep. 18, 2001 discloses a drainpipe test plug to seal a pressurized drainpipe.
U.S. Pat. 6,116,286 issuing to Hooper et al. on Sep. 12, 2000 discloses a pneumatic pipe plug for pipeline tee connections, having a molded cap structure. The air flow regulator extends above the cap, which makes the air flow regulator easy to vandalize.
Manhole covers are disclosed in the following prior art:
U.S. Pat. No. 6,199,414 issuing to Chang on Mar. 13, 2001 discloses a quick release lock for a manhole cover having a radially extended flange. This patent requires slots and catch elements mounted to the cover.
U.S. Pat. No. 5,987,824 issuing to Fuller on Nov. 23, 1999 discloses a locking manhole cover having pivotal locking elements hingedly attached to the frame, and movable locking members biased by interacting cam or gear arrangements.
U.S. Pat. 5,979,117 issuing to Fuller on Nov. 9, 1999 discloses a safety hole cover for drilled and augured holes, with retractable fingers which extend outwardly to engage the side wall of the hole. A tool is inserted through an aperture in the top cap to rotate the fingers.
U.S. Pat. 5,533,641 issuing to Argandona on Jul. 9, 1996 discloses a locking cover assembly with locking levers and a lock actuator movable through the cover.
U.S. Pat. 5,052,851 issuing to Frishauf on Oct. 1, 1991 discloses an emergency maintenance hole cover with an inflatable balloon having a cross-web and a valve extending above the hole.
These prior art patents do not solve the need for a temporary cover that will seal an unfinished opening during construction.
A cover apparatus for temporarily covering access openings for water, drain, manhole and overflow pipes during construction, when the access openings are exposed, to prevent dirt, dust or unauthorized access to the access openings. The cover apparatus includes an arcuate top portion which extends beyond the outer circumference of the access opening, a depending side wall and an outwardly flared lower side wall extending below the depending side wall, which fits within the access opening, which A central ring depends from the top portion in spaced relation from the depending side wall, and a plurality of ribs extending between the central ring and the depending side wall. A pump means is secured within the central ring, and an expandable bladder in fluid communication with the pump means is positioned about the depending side wall, between the top portion and the outwardly flared side wall. When inflated, the expandable bladder expands to seal the cover apparatus to the access opening. An annular ring may be used to position the expandable bladder on the depending side wall between the annular ring and the outwardly flared side wall, for deeper penetration in the access opening.
Therefore, what is needed is a temporary man hole cover that is inexpensive, light weight, and easy to install or remove.
Another object is an inflatable bladder for an access opening, which expands to seal and retain the cover apparatus against the access opening.
Another object is positioning an outwardly inclined flange beneath the inflatable bladder to direct the bladder into a firm engagement with the access opening.
These objects of the invention, together with the various features of novelty which characterize the invention, are pointed out in the claims. For a better understanding of this invention, its operating advantages and the specific objects attained by its users, reference should be made to the accompanying drawings and descriptive matter in which there is illustrated the preferred embodiments of this invention.